1. Field of the Invention
The present invention relates to a TV game machine and, more specifically, to a TV game machine to which a cartridge storing a game program can be freely attached and detached, and which executes a game program by reading the game program from the attached cartridge.
2. Description of the Background Art
A TV game machine executing prescribed game by reading a game program from an attached cartridge (for example TV game machines produced and sold by the assignee of the present application commercially available as the "family computer" and the "Nintendo Entertainment System") have been well known. In such a TV game machine, various games can be played by changing cartridges.
When a cartridge is ejected from the TV game machine in an undesired manner in the middle of the game, reading of the game program from the cartridge becomes impossible. This prevents game play, and it may cause the machine to malfunction. Therefore, a locking mechanism for preventing ejection of the attached cartridge has been proposed.
A TV game machine having a cartridge locking mechanism is disclosed in, for example, Japanese Utility Model Laying-Open No. 2-49595 (known under the commercial name of "MEGA DRIVE" owned by SEGA Enterprises).
The cartridge locking mechanism disclosed in this Japanese Utility Model Laying-Open No. 2-49595 is adapted to lock a cartridge by inserting a pawl portion of an arm member operating in relation to the operation of a power switch to a horizontal notch formed on one side portion of the cartridge.
However, in the above described locking mechanism of the cartridge, only one side portion of the cartridge is engaged. Therefore, when a cartridge is pulled diagonally upward, the cartridge is likely to be pulled out. The cartridge is pulled by one hand. If one tries to pull out the cartridge forcefully with the cartridge being locked, the force is concentrated at the pawl portion of the arm member, which is small. Therefore, the pawl portion or the arm member may be damaged. A TV game machine having an ejecting mechanism enabling vertical ejection of the cartridge utilizing the function of fulcrum, in order to prevent possible damage connecting portions if the cartridge were pulled out diagonally has been known. If the ejecting mechanism is provided in such a TV game machine, by the function of fulcrum, a larger force is applied to the pawl portion or the arm member compared with manual ejection Therefore, the pawl portion and the like tends to be damaged easily.
In addition, when the cartridge is inserted after turning on the power, the TV game machine is likely to be damaged. Therefore, a locking mechanism for preventing insertion of the cartridge after power has been turned on has been desired.